Now thats interesting. Indian Airlines is the domestic arm of Air India. I wonder if they've got these two companies mixed up? Air India stopped flying to Australia in the mid 80's after some disagreement with the Australian Gov't (or was it with Qantas?)
Indian Airlines are now the domestic and "regional international" carrier. They fly to BKK and SIN and a few others I can't think of. The fleet is mainly A320's (nearly 50 of them) however they have a A300's, so if it is them coming to Melbourne I'd imagine they'll be using those old things. Air India would seem more likely, they've just taken some new 777's and are better equipped for long haul.